Transcript Translate output to employment

6-1
Chapter 6
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McGraw-Hill/Irwin
Macroeconomics, 10e
Aggregate Supply:
Wages, Prices,
and Unemployment
© 2008 The McGraw-Hill Companies, Inc., All Rights Reserved.
6-2
Introduction
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Further develop the AS side of the economy and examine the
dynamic adjustment process that carries us from the short run to the
long run
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The price-output relationship is based upon links between wages, prices,
employment, and output
 link between unemployment and inflation = Phillips Curve
Translate between unemployment and output, inflation and price changes
Introduce role of price and inflation expectations, and the “rational
expectations revolution”
NOTE: theory of AS is the least settled area in macro
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Don’t fully understand why W and P are slow to adjust, but offer several
theories
All modern models differ in starting point, but reach the same conclusion:
SRAS is flat, LRAS is vertical
6-3
Inflation and Unemployment
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Figure 6.1 shows U.S. unemployment
from 1959 to 2005
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[Insert Figure 6.1 here]
Several periods of high
unemployment: early 1960s, mid
1970’s, early-mid 1980’s, and early
1990s
Several periods of low
unemployment: late 1960’s, early
2000
Phillips curve (PC) shows the
relationship between unemployment
and inflation
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Although GDP is linked to
unemployment, it is easier to work
with the PC than the AS when
discussing unemployment
6-4
The Phillips Curve
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In 1958 A.W. Phillips
published a study of wage
behavior in the U.K. between
1861 and 1957
[Insert Figure 6.2 here]
The main findings are
summarized in Figure 6.2
 There is an inverse relationship
between the rate of
unemployment and the rate of
increase in money wages
 From a policymaker’s
perspective, there is a tradeoff
between wage inflation and
unemployment
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6-5
Phillips Curve
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The PC shows the rate of growth of wage inflation
decreases with increases in unemployment
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If Wt = wage this period
Wt+1 = wage next period
Wt 1  Wt
gw = rate of wage inflation, then g w 
Wt
(1)
If * represents the natural rate of unemployment, the
simple PC is defined as: g w   (    * ) (2) where 
measures the responsiveness of wages to
unemployment
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Wages are falling when  > * and rising when  < *
( - *) is called the unemployment gap
6-6
Phillips Curve
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Suppose the economy is in
equilibrium with prices stable and
unemployment at the natural rate
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If money supply increases by 10%,
wages and prices both must increase
by 10% for the economy to return to
equilibrium
PC shows:
 If wages increase by 10%,
unemployment will have to fall
 If wages increase, price will
increase and the economy will
return to the full employment
level of output and unemployment
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To see why this is so, rewrite
equation (1) in terms of current
and past wage levels:
Wt 1  Wt
  (    * )
Wt
Wt 1  Wt  Wt (  (    * ))
Wt 1  Wt (  (    * ))  Wt
Wt 1  Wt [1   (    * )]
(2a)
 For wages to rise above previous
levels, u must fall below the natural
rate
6-7
The Policy Tradeoff
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PC quickly became a
cornerstone of macroeconomic
policy analysis since it
suggests that policy makers
could choose different
combinations of u and  rates
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[Insert Figure 6-3 here]
Can choose low u if willing to
accept high  (late 1960’s)
Can maintain low  by having
high u (early 1960’s)
In reality the tradeoff between
u and  is a short run
phenomenon
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In the LR the tradeoff disappears
as AS becomes vertical
6-8
The Inflation Expectations-Augmented
Phillips Curve
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Figure 6-4 shows the behavior
of  and u in the US since
1960  does not fit the simple
PC story
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[Insert Figure 6-4 here]
Individuals are concerned with
standard of living, and compare
wage growth to inflation
• If wages to not “keep up” with
inflation, standard of living
falls
Individuals form expectations as
to what  will be over a particular
period of time, and use in wage
negotiations (e)
Rewrite (2) to reflect this as:
( g w   e )   (    * ) (3)
6-9
The Inflation Expectations-Augmented
Phillips Curve
If maintaining the assumption of a constant real wage,
W/P, actual  will equal wage inflation
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The equation for the modern version of the PC, the
expectations augmented PC, is:
( g w   e )   (    * ) 
(    e )   (    * ),
     (   )
e
*
(4)
NOTE:
1.
2.
e is passed one for one into actual 
u = u* when e = 
6-10
The Inflation Expectations-Augmented
Phillips Curve
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The modern PC intersects the natural
rate of u at the level of expected
inflation
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Figure 6-5 illustrates the inflation
expectations-augmented Phillips
curve for the 1980s and early 2000
The height of the SRPC depends
upon e
Changes in expectations shifts the
curve up and down
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[Insert Figure 6-5 here]
The role of e adds another automatic
adjustment mechanism to the AS side
of the economy
When high AD moves the economy
up and to the left along the SRPC, 
results  if persists, people adjust
their expectations upwards, and move
to higher SRPC
6-11
The Inflation Expectations-Augmented
Phillips Curve
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After 1960, the original PC
relationship broke down
[Insert Figure 6-6 here]
How does the augmented PC hold up?
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To test the augmented PC, need
a measure of e  best
estimate is last period’s
inflation, e = t-1
Figure 6-6 illustrates the
augmented PC using the
equation:
   e     t 1   (u  u* )
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Appears to work well in most
periods
6-12
Rational Expectations
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The augmented PC predicts that actual  will rise above e when u
< u*  So why don’t individuals quickly adjust their expectations
to match the model’s prediction?
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The PC relationship relies on people being WRONG about  in a very
predictable way
If people learn to use (4) to predict , e should always equal , and thus u
= u*
• We predict u = u* in the LR, but this refers to the SR
Robert Lucas modified the model to allow for mistakes
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He argued that a good economics model should not rely on the public making
easily avoidable mistakes
So long as we are making predictions based on information available to the
public, then the values we use for e should be the same as the values the
model predicts for 
Surprise shifts in AD will change u, but predictable shifts will not
6-13
Rational Expectations
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The argument over rational expectations is as follows:
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The usual macroeconomic model takes the height of the PC as
being pegged in the SR by e, where e is set by historical
experience
The rational expectations model has the SRPC floating up and
down in response to available information about the near future
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Individuals use new information to update their expectations
Both models agree that if money growth were
permanently increased, the PC would shift up in the LR,
and  would increase with no LR change in u
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The RE model states that this change is instantaneous, while the
traditional model argues that the shift is gradual
6-14
The Wage-Unemployment Relationship
and Sticky Wages
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In neoclassical theory of supply, wages adjust instantly to
ensure that output always at the full employment level,
BUT output is not always at the full employment level,
and the PC suggests that wages adjust slowly in response
to changes in u
The key question in the theory of AS is “Why does the
nominal wage adjust slowly to shifts in demand?” OR
“Why are wages sticky?”
Wages are sticky when wages move slowly over time,
rather than being flexible, allowing for economy to
deviate from the full employment level
6-15
The Wage-Unemployment Relationship
and Sticky Wages
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To clarify the assumptions about wage stickiness,
translate (3) into a relationship between gw and the level
of employment:
If N* = full employment level of employment
N = actual level of employment
u = share of N* that is not employed, then
*
N
N
  * 
(5)
N*
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Substitute (5) into (3) we have the PC relationship between E, e,
*
and gw:

W

W
N
N
e
e
t 1
t

gw   
    
*
Wt

N

(2b)
6-16
The Wage-Unemployment Relationship
and Sticky Wages
*

W

W
N
N
t

g w   e  t 1
  e   
*
Wt
 N 
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(2b)
The wage next period is equal to the wage that prevailed
this period, but with an adjustment for the level of
employment and e
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At full employment, N* = N, this period’s wage equals last
period’s, plus an adjustment for e
If N > N*, the wage next period increases above this period’s by
more than e since gw - e > 0
6-17
The Wage-Unemployment Relationship
and Sticky Wages
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Figure 6-7 illustrates the wageemployment relationship, WN
The extent to which the wage
responds to E depends on the
parameter 
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If  is large, u has large effects on
wages and the WN line is steep
The PC relationship also implies WN
relationship shifts over time
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[Insert Figure 6-7 here]
If there is over-employment this
period, WN shifts up to WN’
If there is less than full employment
this period, WN curve shifts down to
WN’’
Result: Changes in AD that alter the u
this period will have effects on wages
in subsequent periods
6-18
The Wage-Unemployment Relationship
and Sticky Wages
Each school of thought has to explain why there is a
PC, or the reasons for wage and price stickiness
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Explanations are not mutually exclusive
Examples of such explanations for wage and price stickiness
include:
Imperfect information
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Friedman and Phelps
In the context of clearing markets
Coordination problems
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Focus on the process by which firms adjust their prices when demand
changes
Efficiency wages and costs of price changes
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Focus on wage as a means of motivating labor
6-19
The Wage-Unemployment Relationship
and Sticky Wages
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In developing an explanation of wage stickiness, build upon
mentioned theories and one central element  the labor market
involves long-term relationships between firms and workers
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Working conditions, including the wage, are renegotiated periodically, but not
frequently, due to the costs of doing so
At any time, firms and workers agree on a wage schedule that is to
be paid to currently employed workers
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If demand for labor increases and firms increase hours of work, in the SR
wages rise along the WN curve
With demand up, workers press for increased wages, but takes time to
renegotiate all wages (staggered wage-setting dates)
During the adjustment process, firms also resetting P to cover increased cost
of production
• Process of W and P adjustment continues until economy back at full
employment level of output
6-20
From the Phillips Curve to the AS Curve
The transition from the PC
to the AS curve requires four
steps:
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2.
3.
4.
Translate output to employment
Link prices firms charge to
costs
Use Phillips curve relationship
between W and E
Combine 1-3 to derive upward
sloping AS curve
Translate output to employment
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Close relationship between
unemployment/employment
and output in SR
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Okun’s Law defines this
relationship:
Y Y*
(6)
*
  (u  u )
*
Y
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Estimate  to be close to 2
 each point of u costs 2%
points of GDP
6-21
From the Phillips Curve to the AS Curve
The transition from the PC
to the AS curve requires four
steps:
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1.
2.
3.
4.
Translate output to employment
Link prices firms charge to
costs
Use Phillips curve relationship
between W and E
Combine 1-3 to derive upward
sloping AS curve
Link prices to costs
Firms supply output at a
price that at least covers costs
of production
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Assuming N is the only cost of
production, if each unit of N
produces a units of output, the
labor costs of production per
unit is W/a
Firms set price as a markup, z,
on labor costs:
P
(1  z )W
a
(7)
6-22
From the Phillips Curve to the AS Curve
The transition from the PC
to the AS curve requires four
steps:
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1.
2.
3.
4.
Translate output to employment
Link prices firms charge to
costs
Use Phillips curve relationship
between W and E
Combine 1-3 to derive upward
sloping AS curve
PC, wages and employment
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PC in equation 2(b) gives
wage increases as a function
of e and (u – u*)
 N*  N 

g w     
*
 N 
e
N*  N
*

(



)
where
*
N
6-23
From the Phillips Curve to the AS Curve
The transition from the PC
to the AS curve requires four
steps:
•
1.
2.
3.
4.
Translate output to employment
Link prices firms charge to
costs
Use Phillips curve relationship
between W and E
Combine 1-3 to derive upward
sloping AS curve
The Aggregate Supply curve
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Combining (2b), (6), and (7)
yields:
  Y  Y *  (8)

Pt 1  P  Pt 
*
 Y 
e
t 1
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Often replace (8) with an
approximate version:
Pt 1  P
e
t 1
1   (Y  Y ) (9)
*
which is the equation for the
aggregate supply curve
6-24
From the Phillips Curve to the AS Curve

Pt 1  P 1   (Y  Y )
e
t 1
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*

[Insert Figure 6-8 here]
Figure 6-8 shows AS curve
implied by equation (9)
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If Y > Y*, next period the AS
curve will shift up to AS’
If Y < Y*, next period AS will
shift down to AS’’
NOTE: These are the same
properties as the WN curve
6-25
Supply Shocks
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A supply shock is a disturbance
in the economy whose first
impact is a shift in the AS
curve
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[Insert Figure 6-10 here]
An adverse supply shock is one
that shifts AS inwards (as in
Figure 6-10)
As AS shifts to AS’, equilibrium
shifts from E to E’ and prices
increase while output falls
The u at E’ forces wages and
prices down until return to E, but
process is slow
6-26
Supply Shocks
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After the shock:
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[Insert Figure 6-10 here]
Economy returns to the full
employment level of employment
Price level is the same as it was
before the shock
Nominal wages are LOWER due
to the increased u at the onset of
the shock
Real wages must also fall
W
w
P where w is the real
wage and W is the nominal wage
6-27
Supply Shocks
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Figure 6-10 also shows the
impact of AD policy after an
adverse supply shock
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[Insert Figure 6-10 here]
Suppose G increases (to AD’):
• Economy could move to E* if
increase enough
• Such shifts are
“accommodating policies”
since accommodate the fall in
the real wage at the existing
nominal wage
• Added inflation, although
reduce u from AS shock
6-28